HIV-1 encephalitis (HIVE), is the common pathological correlate of HIV-associated dementia (HAD). The pathogenesis of HIVE revolves around two processes characterized first, by productive replication of the virus in macrophages in the brain, a process that leads to encephalitis, and second, neuronal degeneration that results from by-products of the infected macrophages, leading to dementia. Various complementary tissue culture and animal model systems have provided valuable insights into the pathogenesis of HAD. However, no single model system adequately mimics the human syndrome. The need for development of alternative relevant model systems that are inexpensive, reproducible, and that recapitulate the human disease cannot be thus over-emphasized. The objective of this proposal is to develop a biologically relevant tissue model for the study of HAD. Rotating wall vessel (RWV) bioreactors will be used to establish this advanced 3-D tissue model system. The RWV offers a unique and innovative approach not previously applied toward the study of NeuroAIDS, and will provide a novel model system to explore the neuropathogenesis of HIV-1 infection. The hypothesis to be tested is that neuronal cells co-cultured in the RWV in combination with astroglial cells and macrophages, will functionally mimic the cellular milieu present in HAD. The three-dimensional growth of these cells will provide an improved model system for the study of both HIV-induced neurological disease and for the activation of molecular markers associated with HAD. Validation of the efficacy of our 3-D model will be done by comparison to findings obtained from HIV-infected human tissues and SIV/SHIV-infected non-human primates. Two specific aims are proposed: Aim 1: To establish and characterize a biologically relevant 3-D multicellular co-culture model for the study of HAD using human neuronal cells cultured in combination with macrophages and astrocytic cells. The addition of macrophages and astrocytes to the 3-D models represents an important source of HIV-infectable cells and neuronal support respectively, thereby providing a tissue model that more closely mimics organ structure and function in vivo. Aim 2: To identify HAD-associated molecular markers in the 3-D multicellular co-culture model. HIV-1 infection of the 3-D models and induced alterations in molecular marker profiles will be measured in a context that more closely approximates the parental tissue in vivo and will be representative of changes that occur in the brains of the infected animal host with disease. The goal of this proposal is to develop a novel and innovative research tool for the study of HIV-1 neuropathogenesis. The relevance of this model is its accuracy of recapitulating the cellular cross-talk that takes place in the brains of patients with HIVE, its ease of set-up and reproducibility, and its manipulability for the study of related neurodegenerative diseases. The proposed model also holds tremendous potential for translational research to the clinical bedside for the development and testing of new therapeutics and drugs for HAD, and for the study of other neurodegenerative diseases that affect the central nervous system (CNS). NARRATIVE The overall objective of this proposal is to develop a biologically relevant 3-D tissue culture model for the study of HIV-associated dementia (HAD). This tissue culture model will be established as a co-culture of human neuronal cells in combination with astrocytes and macrophages to better reproduce the total organ environment encountered during the course of infection. The three-dimensional growth of these cells will provide an improved model system for the study of both HIV-induced neurological disease and for the activation of molecular markers associated with HAD. In addition, this novel model system could also have important implications for translational research to the clinical bedside for the development and testing of new therapeutics and drugs for HAD, and for the study of other neurodegenerative diseases that affect the central nervous system (CNS).